In radio systems receivers must contend with a number of sources of potential error, which can include noise from sources external to the system, noise resulting from multi-path effects, and Doppler shift or fade, among others. Dealing with these sources of error is particularly important in modern digital communications where parameters such as symbol synchronization, gain control, and direct current (DC) offset must be addressed to avoid losing synchronization and continue to properly decode incoming data.
Means have been developed that adequately deal with high fading conditions, where a receiver is moving at a relatively high speed from a transmitter, but in deep, slow fade conditions, these means may not be adequate. If not addressed, then these deep, slow fade conditions can cause intermittent communication. Therefore there is a need for a means that detects and corrects receiver operation in deep, slow fade conditions. Such means should not interfere with conventional fade correction that addresses higher fade rates.